Continuous horizontal rotary



[Way 15 1956 DELRUELLE Re. 24,150

commuous HORIZONTAL ROTARY FILTER OF THE TILTING csu. TYPE OriginalFiled Oct. 26, 1950 I 9 Sheets-Sheet 1 INVENTOR.

ANDRE DELRUELLE May 1'5 ,1956' I I Re. 24,150

CQNTINUOUS HORIZONTAL ROTARY FILTER OF THE TILTING CELL TYPE OriginalFiled Oct. 26, 1950 9 Sheets-Sheet 2 INVBWUR ANDRE DELRUELLE BY/PM (WK4. May 15 1956 r A, DELRUELLE CONTINUOUS HORIZONTAL. ROTARY FILTER OFTHE TILTING CELL TYPE on Original Filed Oct. 26, 1950 9 Sheets-Sheet 3INVENTOR. A-NDRE DELRUELLE i 15 1956 A. DELRUQELLE Re. 24,150

CONTINUOUSHORIZONTAL.ROTARY FILTER OF THE TILTING CELL TYPE 9Sheets-Sheet 4 Original Filed on. 26, 1950 INVENTOR. ANDRE DELRUELLE"May 15 1956 DELRUELLE I Re. 24,150

CONTINUOUS HORIZONTAL ROTARY FILTER OF THE TI-LTING CELL TYPE.

Original Filed Oct. 26, 1950 9 Sheets-Sheet 5 INVENTOR. ANDRE DELRUELLEy 1956 V A. DELRUELLE Re. 24,150

CONTINUOUS HORIZONTAL ROTARY FILTER OF THE TILTING CELL TYPE,

Original Filed Oct. 26, 1950 9 Sheets-Sheet 6 Gal vqi 54 63 62 "2 a]Al/M V \q U 11 P72 67 E H i m 73- I 64% l (as INVENTQR. ANDRE DELRLJELLEy 15 1956 A. DELRUELLE Re. 24,150

CONTINUOUS HORIZONTAL ROTARY FILTER OF THE TILTING CELL TYPE OriginalFiled Oct. 26, 1950 9 Sheets-Sheet 7 75 F i Q15 52 I v O F v O 63 V i *1"7-1:; w 67 O INVENTOR. ANDRE DELRUELLE I BYP M Mgy 15 1 956 DELRUELLERe. 24,150

- CONTINUOUS HORIZONTAL ROTARY. FILTER. OF THE T1LTING cs1; TYPE.-

Original Filed Oct. 26. 1950 9 Sheets-Sheet a INVENTOR; ANDRE DELRUEl LEMay 15 1956 A. DELRUELLE Re- 24.1 501 HE TILTING CELL TYPE I commuousHORIZONTAL ROTARY FILTER OF T v 9 Sheets-Sheet 9 1 Original Filed m. 26,1950 INVENTOR. ANDRE DELRUELL BYprMauW I com'nsvous nomzourar. sonarm'rsa or THE'TILTING CELL TYPE Andre Delruelie, deceased, late of Trooz,Belgium, by Martha Clementine Huber-tine Van Leckw'yck Delruelle,

legal representative, Foret, Belgium, nssi'gnor, by mcsne'Pnnanmacorporation of Panama I No. 2 ,ss4,1ss, dated July 20, 1954,Serial No. '1 49, mm 26 July-18, i955, s n-1 No. 531,814 cumpriority,application France October as, 1949 l 7Claims. (Cl.210202.5)i

alignments, to Pannsetals and Proeeu es Inc, Panama,

.. eve M i. 1 1

in the use of expensive corrosion resistant i the liquids beingfiltered, for example acids, 1

. use of such special materials.

, 1950. Application for reissue Matter enclosed in heavy brackets II]appears in the 1 original patent but forms no part of this reissuespecifi- ,catlont matter printed in italics indicates Ithe additionsreissue.

madeby tilting cell type.

Filters of that type possess advantages in that the filter cake can becovered evenly with the washing liquid and can be washed uniformly overits entire area, and in that the residual solution or filtrate presentin the filter cake can be displaced'efliciently by covering the cakewashed several times, this step in the filtration process can beefliciently performed. Filters of the described character operate in acontinuous cycle; each of the cells receiving a charge of the liquid tobe filtered at a selected point during rotation of the apparatus, thenbeing subjected to the-washing liquid at subsequent stations so as toremove the remaining filtrate from the solids and finally being invertedto remove the filter cake or solids from the .cell before it is returnedto an upright position to receive a new charge at the starting point.

By reason of such continuous operation, filters of the described typehave substantially great capacities while making possible accuratecontrol of the filtered liquids.

A specific object of the present invention is to improve The prescntinvention relates to new and useful ir'nprovements .in continuoushorizontal rotary filters of the filters of the character indicated insuch a manner that they can be constructed with substantially enlargeduseful filtering surfaces to increase the yield of the filtrationprocess without requiring any increase in the amounts of the solutionbeing filtered, thusincreasing the etiiciency of the filter.

Another object is to provide filter cells of light construction so thatthe area of the filter. surface may be substantially increased withoutefiecting a resultant increase in the mass of the apparatus.

Another object is to provide a filter of the character describedincluding a frame rotating about a central liquid distributing deviceand carrying filtering cells in a manner so that the latter can betilted, wherein each of thecells is connected to the head of thedistributing device by a flexible tube and a driving connection betweenthe rotating frame and the head of the distributor is formed to, permitdisplacement of the frame relative to the head so that the rigidtolerances required in the construction of the distributing device neednot be applied to the remainder of the filter structure and the lattermay cell in a clean condition. I Another object is to provide afiltering apparatus of the character indicated wherein the filtercellsare of light construction and have flat bottoms and wherein eachcell is tilted to an inclined position, with the outlet thereof,

Another object is to provide filters of the an em- 1 indicated withimproved means for eliecting and control-1 ling the tilting movements ofthe filter cells so that filtrjation proceeds during the greater part ofthe rotational cycle of the cell and the latter is' inverted at the endof the cyclev for rapidly and completely discharging the filtered solidor filter-cake from the cell to maintain lowermost, at 'the end of thewashing phase of the operatin'g cycle and maintained in such inclinedposition.

for a specified period while a vacuum is applied thereto to effectcomplete withdrawal of the filtered acids from the cell prior toinverting the latter for disposal'of the I -A further object of theinvention is to provide a filtering apparatus of the character indicatedwherein a vacuum is applied to each filter cell before the latterreceives a new charge to thereby remove all washing water from the cellso that the acid of the new charge willnot be diluted.

The foregoing and otherobjects, features and advantages of the inventionwill become apparent from the following detailed description of anillustrative em bodiment thereof. While the described embodiment hasbeen provided particularly for separation of gypsum and phosphoric acidduring the industrial production of that acid by the wet process, thenew features of combination, construction and operation which areclaimed as the invention are not limited to this precise application,and filters constructed according'to the invention may be advantageouslyemployed in any large scale industrial filtration process, particularlywhere it is desired to provide several successive washing steps.

The detailed description refers to the accompanying drawings which formpart hereof and in which:

Fig. 1 is a partial top plan view of a rotary filter. constructedaccording to an embodiment of the' invention and showing the structurecarrying one of the tilting filter cells; a I

Fig. 2 is a side elevational view, partly in section, of the device ofFig. 1;

Fig. 3 is an outerend elevational view, on an en larged scale, of thefilter cell of Fig. 1;

Fig. 4 is a longitudinal vertical section, on an enlarged scale, of thefilter cell of Fig. l; I v Fig. 5 is a top plan viewof the supportingstructure for the filter cell;

Fig. 6 is a fragmentary end clevational view, on an enlarged scale, ofthe filter cell of Fig. 4;

Fig. 7 is a fragmentary, longitudinal vertical section,

on an enlarged scale, to show the details of construeing a part of thefilter cell of Fig. 9;

be light in weight tothereby efiect substantial economy Fig. 11 is afragmentary transverse vertical sectional view of the filter cell ofFig. 9, taken along the line XI-XI 0f Fig. 10;

'. Fig. 12 is a longitudinal vertical sectional view, similar to Figs. 7and 9, but showing a filter cell constructed Ma M a w ul 7 according tostill another embodiment of the invention. -Fig. 13 is a diagrammaticillustration of the track structure provided for effecting the'tiltingof the several filter cells as the latter are rotated;

Fig. 16,. is a fragmentary plan view of a portion ofthe fixed supportfor the distributing device;

Fig-l7 is a plan view of a half of an element included in thedistributing device;

Fig. 18 is a vertical sectional view, on an enlarged scale, taken alongthe line.XVlIl-XVlll of- Fig. l7;

Fig[ 19 is a plan. view of another element included in the distributingdevice; Y

Fig. 20 is a vertical sectional view taken along the line XX-XX of Fig.19; g Fig. 21 is a fragmentary sectional view taken along the lineXXl--XX[ of Fig. 19;

Fig. 22 is a fragmentary sectional view taken along the line xxu xxn ofFig. 19; 1

Fig. 23 is a plan view of still another element included in thedistributing device;

, Fig. 24 is a plan view of a half of the structure provided for drivingthe distributing device;

Fig. v25 is a vertical sectional view taken along the .line XXV-XXV ofFig. 24; and

Fig. 26 is a fragmentary vertical sectional view taken foundation 11,preferably formed of brick-work ormasonry, supporting concentric,circular inner and outer tracks or guideways 9 and 10. An annular frame6 is provided with inner wheels 7 riding on track 9 and outer flangedwheels B'riding on outer track so that frame 6 is rotatable in ahorizontal plane above base 11.

-A.circularlyarranged series of filter cells 1, each being in the formof an isosceles trapezoid, is'mounted on the frame 6 in such a mannerthat the cells are capable of being individually tilted aboutradiallyextending axes. 'To permit such tilting of the cells 1, each ofthe latter is fixed on a supporting frame 2 which includes a radiallyextending shaft 3 journa'lled adjacent its opposite ends in-bearings 4and 5 carried by frame 6. Thus, the loads of the filter cells are takenup adjacent their inner and outer ends by the bearings 4 and 5 anddistributed directly to theunderlyingtracks through frame 6 and wheels 7and 8. By reason of the described supporting structure, bending stressestherein are kept at a minimum and, therefore, the Weight of the varioussup porting elements may be reduced to economize on the amount ofcorrosion-resistant material employed.

Similar economies are further realized by effecting the driving of frame6 at the periphery of the latter. For this purpose, a toothed rack 13extends along the inner peripheral edge of frame 6 and is engaged by apair of driving pinions or toothed wheels 12 (only one being shown inFig. 2)' which are located at diametrically opposed points. A motor 14is mounted within the central well or pit formed by the base 11 and issuitably coupled to a transmission gearing arrangement 15 for reducingand varying the rotational speed of frame 6.

One of the driving pinions 12 is coupled directly to the transmissiongearing, while a shaft 16 extends from the ends of the arms thereof.

of travel of the outer periphery of frame 6 and support an outer camtrack 20, upon which roller 18 rides, and an innercam track 21, uponwhich roller 19 rides. The tracks 20 and 21 are provided with undulatingforms, hereinafter specifically set forth, to control the position ofeach filter cell as the latter proceeds through a cycle of operation sothat a cell of lightweight construction may be used without decreasingthe efficiency of the filtration process.

In the embodiment of the invention illustrated in Figs. 4-8, each celllhavi'ng the plan form of anisosceles trapezoid includes a flat,thin,'bottom plate 22, an intermediate element or false bottom 23overlying bottom plate 22 to support the filter cloth, and an inclinedside wall or frame 24 of thin sheet metal'extending around the marginsof the bottom plate and false bottom. The lower edge of side wall 24 isbent outwardly and fastening elements, such as bolts, extend throughthis outwardly bent portion of theside wall, the false bottom and thebottom plate and into the frame '2 to secure these elements together.Bottom plate 22, side wall 24 and fastening elements 25 are preferablyformed of a stainless steel, while false bottom23 is formed of rubber orany other similar material so that all parts of the filter cellwithstand or resist attack by acids, particularly phosphoric acid. Thus,the filter cell is light in weight, may be easily assembled or,disassembled, and is suitable for the filtration of liquids of an acidnature.

The false bottom 23 includes an imperforate marginal portion, to insurea liquid 'tight joint between side wall 24 and bottom plate 22, and acentral portion which is provided with a flat upper surface and arecessed lower surface having projections or bosses 28 to engage thebottom plate. False bottom 23 is further formed with a multitude ofsmall openings 27 extending from the flat upper surface and opening,into the recess at the bottom surface between bosses 28 so that liquidmay drain through openings 27 into the space between the central portionof false bottom23 and plate 22 (Fig.7.). A filter cloth 30 covers thetop surface of false bottom 23 and the latter is formed with undercutgrooves 29 open ing at its top surface along the marginal portionsthereof to receive rods 31 for wedging the edge portions of the filtercloth therein. Thus, the filter cloth is maintained in a taut conditionto cover false bottom 23 and the forces holding the cloth in positionare distributed along the edges thereof rather than being localized, andyet the cloth may be easily replaced. Finally, an opening 32 is formedin bottom plate 22 to open into the recess in the bottom surface offalse bottom 23 and to receive the liquid draining through the latter.In order to ensure the complete draining of this liquid from the placeabove bottom plate 22, opening 32 is positioned at a corner of the outerlarger side of the isosceles trapezoid defining the plan form of plate22 (Fig. 5) so that the opening will be lowermost when the filter cellis tilted about shaft 3.

In Figs. 9-11 at filter cell constructed according to am otherembodiment of the invention is illustrated and includes a bottom plate34 formed with corrugations ex,- tending at right angles to the axis ofrotation of shaft 3 and a false bottom 33, formed of rubber or othersimilar material, overlying the corrugated bottom plate to support thefilter cloth. False bottom 33 is formed with openings 27 so that theliquid being filtered may pass therethrough into the channels 35 formedby the corrugations of plate 34. A groove or liquid collecting chan--nel 36 is formed in bottom plate 34, and extends along a side edge ofthe latter to outlet opening 32 at one ofthe outer corners thereof.

Fig.12 is a sectional view similar to Figs. 7 and 9 but taken through afilter cell constructed according to still another embodiment ofthe'invention. The filter cell of Standards 49 are fixed in the base 11at spaced intervals outwardly ofthe path Plg. 12 includes a flat, thinbottom plate 22 and a false' as "Bakelite," or other similar plasticmaterial, and .hav-

ing grooves 35 in the top surface thereof extending transversely or atright angles to the tilting axis of the cell and communicating at oneend with a collecting groove or channel, similar to the channel'36 ofFig. 11, extending along one side edge of the cell for directing. thedrained liquids to the outlet formed in an outer corner of plate 22.

By reason of the bosses 28 of Fig. 7, the corrugations of the bottomplate 34 of Fig. 9, or the undulations of e the element 37 of Fig. 12,it is possible to apply a very high'vacuum to the space between thefilter cloth and the bottom plate of the filter cell during certainperiods of the continuous filtration process without collapsing.

or otherwise distorting the structure of the bottom of the filter cell,even though the construction of the latter is primarily of light weightacid resistant material. That is, the bottom plate and the filter clothare held apart in each embodiment at points spaced over their entireareas so that the force of atmospheric pressure tending to collapse thebottom plate when a high vacuum is applied to the space between thebottom plate and filter cloth is resisted evenly at these many pointsrather than being concentrated. v I

The filter cells 1 are successively charged or filled as they pass undera charging tank 38 (Fig. 2) which is suspended from a track 39 disposedabove the rotary filter so that the charging station may be disposed atany desired position. A pipe 40 openinginto tank 38 supplies thematerial to be filtered, for example gypsum sludge or slurry dischargedfrom a plantfor manufacturing phosphoric acid.

After the liquid has been filtered through the'filter cloth in each cellit is withdrawn from the cell through outlet opening 32 of the latterinto a pipe 41 which is connected'atits outer'end to opening 32.According to the invention, pipe 4l is fiexible, preferably ofarmoredrubber construction, and capable of withstanding twisting ortorsional displacements of 180 between its ends. The inner end of eachpipe 41 is fixed to a compartment or section of a rotatable head,generally indicated by the reference numeral 42 in Figs. 1 and 2,carried by a central distributing device 43 which is mounted fixedly ona supporting frame or pedestal 44. Since the pipes 41 are flexible andcapable of twisting action, the opposite ends thereof may be securelyattached to the bottom plates of filter cells 1 and to the respectivesections of distributor head 42, and still permit tilting of the filtercells. Thus, no rotatable or movable sealing glands or joints arerequired at the ends of pipes 41 and a more complete seal may beeffective to prevent the leakage of liquid or air past these joints.Furthermore, the flexibility 4 of pipes 41 permits the true rotation ofdistributor head 42 unafi'ected by any irregularities in the rotationalpath of filter cells 1 or frame 6, and the rigid tolerances required inthe manufacture of the parts of the distributor need not be extended orapplied to the remainder of the filter structure.

The function of distributing device 43 is to place the several pipes 41in communication with various vacuum separators-andwith the atmosphereat stages during the operating cycle of each filter cell 1 so that thefiltering will proceed with optimum efficiency. The operating cycle ofeach filter cellmay be considered to begin when the cell passes undertank 38 to receive a charge of, for

example, gypsum sludge or slurry including phosphoricacid. Aswill beseenhereinafter, the cell is level, clean and dry when receiving the chargeat the start. of its operating cycle, and pipe 41 is in communicationthrough the distributor with a vacuum separator to maintain a .vacuum of300 to 400 mm. of water column underthe filter cloth for effectingtheeven distribution of the charge over the entire surface of the filtercloth. After charging of the cell is completed, the latter continueslevel or horizontal, and the pressure within thecell, that is under thefilter cloth, is further decreasedvthrough the action'ot the distributorfor the entire period duringwhich the filtration of the mother liquid,in the illus' trated case the phosphoric acid,-a'nd thevarious washliquids takes place. The wash liquid is applied evenly to the successivecells by a weir distributor, also supported on the overhead trackway 39for positioning at any desired location.

Before receiving a new charge, each cell must be drained of the liquidremaining therein, and the filter cake, in the illustrated case thegypsum, removed. There fore, the tracks 20 and 21 are so formed thateach cell is inclined approximately 45 near the end of the washing stageand continues so inclined for an extended period,

with the opening 32 in the bottom thereof lowermost,

so that the liquid completely drains through the outlet opening and nopools of liquid collect on the bottom plate of the filter cell by reasonof irregularities in the surface of such bottom plate resulting from thethin material of which the latter is formed. This arrangement insureseffective washing and complete recovery of the filtered acidi After thefilter "cell has been tilted as above to provide for the completedraining of the liquids, rollers 18'and 19 of the filtercell engageportions of the respective cam tracks which are formed tofurther tiltthe cell to an inverted or upside-down position and during 'thisphase ofthe operating cycle the distributor places the interior of the cell incommunication with the atmosphere so that the filter cake is free todrop out of the cell. Suitable jets may be positioned atthe filter cakedumpingstation to spray water on the filter cake and thereby loosen itfrom the cell.

Further rotation of frame 6 brings the filter cell rollers 18 and 19 incontact with portions of the cam tracks effecting the return of the cellback to its original or horizontal position and the distributor thenplaces pipe 41 in communication with a vacuum creating device to efiectan air fiow through the filter cloth for-drying the latter and forremoving any pools of water that may'have collected on the bottom plateof the cell so that the acid in the subsequent charge received by thecell'will not be diluted.

Referring now to Fig. 13, portions of the cam tracks are there showndiagrammatically to illustrate the ac tion of such tracks in initiallytilting, then inverting and finally righting the filter cells as thelatter move through the above operating cycle. lo the diagram, thefilter cells travel from left to right with the shaft 3 moving along ahorizontal path indicated by a broken line. Beginning at the left, theends of horizontal stretches of cam tracks 20 and 21 are shown overwhich rollers 18 and 19, respectively, ride during the charging andwashing phases of the operating cycle. Since the rollers 18 and 19 aredisposed at opposite sides of the tilting axis of the cell and bothrollers engage above the horizontal stretches of tracks 20 and 21,thecells are positively held against tilting in either direction duringsuch charging and washing phases. As the cell approaches the end of thewashing phase, cam track 21 terminates in an upwardly inclined section21a while track 20 dips so that the cell is tilted approximately 45.Track 20 after dipping, as noted above, continues horizontally at alower level and roller 18 is held in contact with the depressedhorizontal portion of track 20 by an overlying parallel cam tracksegment 20a. Thus, the cell will continue its movement in an inclinedposition (shown at A) so that the wash liquid may be completely drainedtherefrom as indicated above in the explanation of the operating cycle.Track 20 and overlying segment 20a terminate at the filter cake dumpingstation in downw'ardly inelinedportions to further depress roller 18 andinclin'c the cell until the center of gravity of the cell passes aheadof the tilting axis thereof and the cell thereby tips over tothcinverted position B. Since this tipping over by reason of thedisplacement of the center of gravity may be prevented, for example byuneven vdistribution of the charge in the cell or by jamming or cloggingof the bearings 4 and 5, a downwardly curving cam track segment 21bextends over the downwardly inclined portions of 20 and 20a to engageroller 19 and further urge the cell to the inverted position ll.

From 'the dumping station, cam track sections 21 and Zlc inclineupwardly to engage under and above roller [9 so that the cell isgradually tilted back to a vertical position. Atthe, end of the upwardlyinclining path defined by track section 21c and the underlying sectionot'cam track 2l av bumper 50 is positioned to momentarily arrest themovement of roller 19 while the shaft 3 continues along its horizontalpath of travel. Thus, the

cell is further tilted back towards its upright or level position, andsuch righting of the cell is completed by the track section 20b andunderlying section of cam track 20 which curve upwardly and engage aboveand below, respectively, roller 18. Cam track 20 then continueshorizontally and the horizontal portion of track 21 starts again toengage under rollers 18 and 19, respectively, and maintain the cell in alevel and upright condition C during the charging and washing phases ofthe repeated cycle of operation. I

From the above description of the cooperative action ofthe variousportions of cam tracks 20 and 21 and rollers 18 and 19, it is apparentthat the successive tilttively controlled in an automatic and positivemanner as the frame 6 rotates, and further that this control is achievedwithout imposing'excessive strains upon the arms of bell-crank 17 due tothe light construction of the cell and the closeness of the center ofgravity thereof to the tilting axis. It is also apparent that theangular relationship of the arms of bell-crank 17 positions at least oneof the rollers 18 and 19 ahead of the tilting axis at all times so thatvertical forces acting on such leading roller etfecta substantialturning moment about the tilting axis. I I i In Figs. 14-23 the detailsof construction of 'distributing device 43 are illustrated. Thedistributing device includes a stationary central core 70 which is heldby bolts 71 or otherwise fixed on top of supporting pedestal 44. Core 70is formed with spaced radially extending projections 70a (Fig. 16). Anannular casing 69 fits around core 70 and is formed with radialpartitions 83 (Fig. 23) which divide the interior thereof into aplurality of chambers. in the illustrated embodi ment. casing 69 isformed with openings 86, 87, 88, 89, 90, 91 and 92 in the top thereof,each opening into a separate chamber. an outlet opening in the bottomthereof and a pipe section extends therefrom (Fig.'.l4) to facilitatethe attachment of conduits to the casing and also to engage betweenprojections 70a of the central core and thus prevent rotation of casing69.

The chamber having opening 9! in its top is suitably communicated withthe atmosphere through the opening '84 in the bottom thereof, while apipe 45 connects to the pipe section extending from the opening 85 ofeach of the other chambers and communicates the latter with a vacuumseparator 46 (Fig. 2) through a T-coupling 47. .A pipe 48 is connectedto the remaining leg of the coupling and-the liquid is separated fromthe gases and vaportswhile flowing through the latter, thereby formingabarometric column. 7 I

Rotatable head 42 of the distributing device includes a ring member 51formed with a plurality of radially extending pipe sections 52 eachhaving a flange on the outer end to provide for attaching flexible pipes41 thereto. Ring member 51 is further formed with axially extendingpassages 67 into which radial pipe sections 52 open. A circular cover 53is fixed to the top of ring member 51 by fastening screws 54 and closesthe upper ends of passages 67. i i

A bushing ring 64 (Figs. 14 and 17) is secured to the bottom of ringmember 51 by screws set in countersunk holes 65. Bushing ring 64 isformed with axially extending ports 66 communicating with thepassages 67of ring member St and bears on a distributing ring 68 fixed to the topof annular casing 69 so that the head is supported rotatably on thestationary parts of the distributing de- .vice. The rotatable. head iscentered with respect to stationary core 70 by a ring 72, formed ofbr0nze,-or other similar material, which is securedto the interior ofring In order to provide for rotation of head 42 synchronously with therotation offrame 6 and the movement of the filter cells through theiroperating cycles a square boss or projection 55 is secured by the bolts62 at the center of cover plate 53 and is engaged by a driving assemblycarried by frame 6. The driving assembly includes radial arms 56extending towards the center of rotation from frame 6 and carrying acircular ring 57 at their inner ends (Fig. 1). I

The circular ring 57 carries a structure, seen in detail in Figs. 24-26.for loose engagement over boss 55 to permit limited movement of theframe 6 independent of the distributing device. In the illustratedembodiment this structure includes a pair of rigid cross-beams 58secured at their opposite ends to ring 57 and carrying spaced guidemembers 59, and a sliding frame 60 resting oncross-beams 58 and guidedin movement at right angles to the latter by the guide members. Slidingframe 60 is provided with a pair of beams 61 extending parallel tocross-beams 58 and defining a rectangular opening having a largedimension in the direction of the crossbeams 58 and a smaller dimension,just large enough to receive the square boss 55 of the distributor headin the direction of the, movement of sliding frame 60 relative Eachchamber is also'formed with to the cross-beams.

I Thus, boss 55 is free to move vertically and also horizontally, in thedirection parallel to cross-beams 58, within the sliding frame, and thelatter is free to move horizontally at right angles to beams 58.

Since the above construction provides a flexible connection betweenframe 6 and distributor head "and the only other connection therebetweenis by flexible pipes 41, lateral stresses resulting from irregularitiesin the path of travel of frame 6 or filter cells 1 are not imposed uponthe distributor head. it is also apparent that the driving connectionbetween frame 6 and the distributor head imposes no vertical load on thelatter so that the bushing ring 64 and distributor ring 68.0f thedistributor may be formed of a material which does not possessgreat'mcchanical strength, such as those including'graphite or asynthetic resin and asbestos, for example, the material known by thetrade name Haveg." but has superior qual ities in resisting attack byacids and in providing wear ends with the openings 86. 87. 88, 89, 90.91 and 92,

respectively, in the top wall of casing 69. The shape of the passages 76to 82 at the upper surface of the distributor ring determines theduration of thesuccessive port of bushing ring 64 is aligned with the ofthe distributor ring between the passages 76 and 82.

- phasesof the filtration cycle during one rotation of the apparatus;

During the charging of a filter-cell, the corresponding solid portion Asthe filter cell moves through an operating cycle, its

port in the bushing ring registers successively with port A 76, as themother liquor is filtrated, port 77 for the first washing step, port. 78for the second washing step, port 79 for the third washing step withwater, port 80 for the end phase of the washing step until the-cell isinclined, port 81 for the step during which dumping of the filter cakeis efiected at which time the interior of the cell-is in communicationwith the atmosphere through opening 84, and port 82'for the righting ofthe cell when a vacuum of 300 to 400 rnm.of water column isapplied todry the filter cloth and remove any residual liquid in the cell.

it should be noted that an improved operating cycle results from theinclusion of ports 80 and 82 in the distributor ring, since these portsapply vacuum to the vinterior of the cell when the latter is tiltedbefore being inverted to withdraw all of the acid therefrom and when thecell is being righted to prevent any water remaining therein fromdiluting the new charge. By reason of these improved phases of theoperating cycle, flat'bottomed filter cells may be efficiently employed.

It is also apparent that the filtering apparatus described aboveprovides perfect centering of the rotatable head of the distributor, theuse of appropriate materials to achieve good sliding contact between thedistributor ring and the bushing ring of the distributor head and tightjoints at the opposite ends of the flexible pipes extending from thedistributor head to the several filter cells so that the possibility ofloss of the filtered acid through leakage tributions to the art, whichare intended to defined by the appended claims.

What is claimed is: v

l. A filter cell for a continuous, horizontal, rotary filter of thetilting cell type comprising a'substantially -planar bottom havinginwardly converging side edges and formed with an outlet opening in oneof the outer cornerportions thereof, a resilient false bottom overlyingsaid bottom and being coextensive with the latter,

upstanding'walls extending along the marginal portions of said falsebottom and formed with flanges on the I ,"lOWCl' edgcs'to overlie saidmarginal portions, means extending through and securing together said.flanges,

said marginal portions and said bottom, means defining passages betweensaid false bottom and said bottom 'in communication with said outletopening, said false bottom having openings formed therethrough withinthe area of the false bottom defined by said upstanding walls, saidopenings communicating with said passages, a filter cloth extending oversaid false bottom, and means securing the edge portions of said filtercloth to said false bottom. f

2. A filter cell according to claim 1, wherein the last mentioned meansincludes undercut grooves opening at the .top surface of said falsebottom and extending along said marginal portions of the latter, andelongated rods engaging above said edge portions of the filter cloth andwedging into said grooves so that the securing forces are distributedalong the edges of said filtercloth.

3. A filter cell according to claim 1, wherein said bottom is flat andsaid means defining passages includes a'recess formed in the under sideof said false bottom and opening-into' said outlet opening and spacedpro- 10 I jections in said recess for engagement with said bottom.

4. Afilter cell according to claim 1, wherein said means definingpassages includes transversely extending corrugations formed in the areaof said bottom underlying said openings of said false bottom and a.channel extending along one side edge of said bottom to open at one endinto said outlet opening and at the side thereof into the adjacent endsof said corrugations.

5. A filter cell according to claim 1, wherein said bottom is flat andsaid means defining passages includes a rigid spacing member interposedbetween said bottom and said false bottom, said spacing member beingformed with transversely extending grooves in the top surface thereofcommunicating with said openings in the false bottom and with a channelalong one side edge opening at one end into said outlet opening and atthe side'into,

the adjacent ends of said transversely extending grooves.

6. In a continuous, horizontal rotary filter including an annular framerotatable about a central vertical axis, a circularly arranged series offilter cells carried by said annular frame for tilting about radiallyextending horizontal axes and for successive movement through charging,filtering, washing and filter cake discharging stations, the combinationof a centrally located fluid distributing device including a fixedbody,an annular upwardly facing distributor ring carried by said body andformed with circumferentially spaced ports for communication with vacuumseparator devices and the at mosphere, a head rotatable on said bodyabout an axis substantially coinciding with said vertical axis andformed with passages opening radially and downwardly at their oppositeends, an annular bushing ring on said head bearing downwardly on saiddistributor ring and formed with .circumferentially spaced openingscommunicating withsaid passages and successively registering with saidports as the head is rotated, flexible conduits extending between. thefilter cells and the radially opening ends of said passages, and meanscarried by the frame and vertically as well as radially displaccablerelative to said head for driving the latter so that the frame exerts noradial or vertical forces on the head and said bushing ring anddistributor. ring may be formed. of a material effecting a liquid tightseal at their meeting surfaces but having a relatively low strengthunder compression.

7. A continuous rotary filter of the tilting cell type comprising anannular frame, a series of. filter cells carried by said frame, a'fluiddistributing device arranged centrally of the annular frame and having ahead rotatable about a central vertical axis, flexible conduitsconnecting the filter cellsto the fluid distributing device,

drive mechanism operative upon the annular frame to rotate it about anaxis substantially coinciding with said vertical axis, the filter cells'being'tiltable relative to the annular frame about substantiallyhorizontal axes radially disposed with respect to the axis of rotationof the frame, coupling means between the annular frame and the rotatablehead of the distributing device, said coupling means comprising a drivenmember fixed to said head and a cooperating driving member carried bythe annular frame, said driven and, driving members being vertically andradially movable relative to one another, and cam trackways arrangedcircumferentially with respect to the annular frame for engagement withcam elements operative upon the filter cells to tilt the cells.

8. A continuous rotary filter of the tilting cell type comprising anannular frame, a series of filter cells carried by said frame, a fluiddistributing device arranged centrally of the annular frame and having ahead rotatable about a central vertical axis, flexible conduits con-'disposed with respect to the axis of rotation of the frame,

11 coupling means between the annular frame and the rotatable head ofthe distributing device, said coupling means comprising a driven memberfixed to said head and a driving assembly carried by the annularframe,said driving assembly including a support fixed to the annular frame,and a sliding frame carried by the supportand movable linearly andhorizontally relative to the -latter,- said sliding frame engaging saiddriven member and being movable both vertically and horizontally atright angles to the direction of movement of said sliding frame relativeto said support, and cam tracltways arranged circumferentially withrespect to the annular frame for engagement with cam elements operativeupon the filter cells to tilt the cells.

" 9. A continuous rotary filter of the tilting cell typecomprising-horizontal circular supporting tracks, air annular framemounted on said tracks, a series of filter cells carried by said frame,a fluid distributing device arranged centrally of the annular frame andhaving a head' rotatable about a central vertical axis, flexibleconduitsconnecting the filter cells to the fluid distributingdevice-drive mech--anism operative upon the annular frame to-rotate it about an axissubstantially coinciding with said vertical axis, the filter cells beingtiltable relative to the annular frame about substantially horizontalaxes radially disposed with respect to the axis of rotation of theframe, coupling means between the annular frame and the rotatable headof the distributing device, said coupling means comprising a flatsidedprojection centrally located on the top of said head and a drivingassembly carried by the annular frame,

7 said driving assembly including a support fixed to the annular frame,and a slidingframe freely carried by said support-and formed with anelongated straight-sided opening receiving said flat-sided projectionand movable vertically as'well as radially parallel to the fiat sides ofsaid projection relative to the latter, and guide means on said supportengaging said sliding frame to restrict radial move ment of the latterrelative to said support tothe direction at right angles to thedirection of the radial movement of said sliding frame relative to saidprojection, 'cam trackways arranged circum'ferentially with respect tothe annular frame for engagement with cam elements operative upon thefilter cellsto tilt the cells.

10. A continuous, horizontal, rotary filter of the tilting cell typecomprising. anannular frame rotatable'about a central vertical axis, acircularly arranged series of upwa-rdly opening filter cells carried bysaid frame and tiltable about radially extending horizontal axes, eachof said cells having a horizontal bottom and'lateral sides converging'towardthe center of rotation of said frame and an outlet opening fordraining fluid from the cell formed in one of the outer corner portionsof said bottom,

7 cam elements carried by each of saidcells, and cam trackways arrangedcircumferentially with respect to the annular frame for engagement withsaid cam elements to hold said cells inclined downwardly toward theirrespective fluid outletopenings in part of their path of rotation Iabout said axis and then further to tilt the cells.

ll. A continuous, horizontal, rotary filter of the tilting cell typecomprising an annular framejrotatable about a .central vertical axis, acircularly arranged series of upwardly opening filter cells carried bysaid frame and .tiltable about radially extending horizontal axes, eachof said cells having a horizontal bottom and lateral sides convergingtoward the center of rotation of said frame and an outlet opening fordraining fluid from the cell' formed in one of the outer corner portionsof said, bottom, and a filterclothextending over and'spaced from saidbottom, and a fluid distributing device arranged centrally of theannular frame and connected to said outlet openings.

l2. A continuous, horizontal, rotary filter of the tilting cell typecomprising an annular frame rotatable about a central vertical axis; acircularly arranged series of filter cells carried by said frame andtiltable about radially extending horizontal axes, and means controllingthe posi- 12 tion of each of said. cells two obtusely related cam armsfixed to each filter cell and extending forwardly and rearwardly,respectively, of the- I tilting axis of the related filter cell. whenthe latter is upright so that at least one of said cam arms is at alltimes inclined relative tothe vertical plane passing through saidtilting axis, and two cam tracltways each engageable by one of said twocam arms, said trackways being arranged circumferentially with respectto the annular frame and at different radial distances from saidverticalaxis and having horizontal portions and overlapping inclinedportions, the horizontal portionsbeing located at difierent levels, byreason of all of-which the cells are maintained Y in level uprightposition during part of their cycle of travel about said vertical axis,in inclined position during another part of the cycle, and inverted atanothertpoint of the cycle, and are restored to their level uprightpositionto I repeat the cycle.

13. A continuous, horizontal, rotary filter of the tilting cell typecomprising an annular frame rotatable about a central vertical axis; acircularly arranged series of filter cells carried by said frame andtiltable about radially extending horizontal axes and for successivemovement through charging, filtering,. washing and filter-cakedischarging stations during each revolution of said frame; and meanspositively controlling the position'of each of said cells as said framerotates includingfirst and second cam arms fixed to each filter cell andextending forwardly and rearwardly, respectively, as-well as above thetilting axis of the related filter cell when the latter is upright sothat at least one of said cam arms at all times extends ahead of saidtilting axis, and first and second camitrackways engageable with saidfirst and second cam arms, re-

I spectively, said first and second trackways being formed withhorizontal portions extending opposite said charging and filteringstations and a substantial initial portion of clines downwardly todepress the engaged second cam arm and invert the cell, sa id secondtrackway inclining upwardly from a point just beyond said filter cakedischarging station to return said second arm to a vertical positionwhile said first trackway engages said first cam arm when said secondarm is vertical and inclines upward- 'ly to raise said first arm andrestore said related cell to upright position at a point in advance ofsaid charging station. I a

14, A continuous, horizontal, rotary filter of the tilting cell typecomprising an annular frame rotatable about a central vertical axis, acircularly arranged series of upwardly opening filter cells carried bysaid frame and tiltable about radially extending horizontal axes, eachof said cells having a horizontal bottom and lateral sides convergingtoward the center of rotation of said frame and an outlet opening fordraining fiuid'from the cell formed in one of the outer corner portionsof said bottorn, a resilient false bottom overlying said bottom, saidfalse bottom being formed witha multiplicity of filtration openingsextending therethrough, means definingfree fluid passages between saidbottom and said false bottom and in communication with said-outletopening, and la filter cloth extending over the top surface of saidfalse bottom.

15. A continuous rotary filter of the tilting cell type comprisinga-massive annular frame, ;a series of filter cells carried by saidframe, a fluid distributing device mounted independently and centrallyof the annular frame as said frame rotates including said frame. andflexible fluid conduits respectively connecting said filter cells withsaid head, said driving means holding said head against angulardisplacement relative to said frame in the direction of said rotationbut keeping said frame freely displaceable radially and verticallyrelative to said head as it is rotated about said trackway. 16. Acontinuous rotary filter of the tilting cell type comprising a massiveannular frame, a series of filter cells carried by said frame, a fluiddistributing device mounted independently and centrally of the annularframe and having a head rotatable about a central vertical axis, drivemechanism operative upon the annular frame to rotate it about an axissubstantially coinciding with said 14 without the provision of movablesealing glands and'the annular frame is freely disploceable radially andvertically relative to said head as it is rotated about said trackway.I7, A continuous rotary filter of the tilting cell type comprising amassive annular frame, an annular trackway supporting said frame, aseries of filter cells carried by said frame, a fluid distributingdevice mounted independently and centrally of the annular frame andhaving a head rotatable about a central vertical axis. drive mechanismoperative upon the annular frame to rotate it about an axissubstantially coinciding with said vertical axis, a series of hollowshafts mounted radially on said frame, each of said cells beingsupported on one of said shafts and being tiltable relative to saidframe by rotation of the supporting shaft, and flexible fluid conduitsrespectively connecting said filter cells with said head, said flexibleconduits extending through said hollow shafts.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS

